When neutral runs to earth

[Brownout]

Hi, I'm in Australia. I suppose the question includes the safety issue of just how much further than changing a llightbulb should a DIY go? And some would rightly say, "No further," but realistically that's rarely the case.
In my case my sister hosed down the outside of her house, including some of the light fittings and tripped the circuit breaker on one of the lighting phases. The breaker wouldn't re-set, so she called me. Because the fitting had all carboned up and the light was blown I changed both the bulb and the fitting.
I don't know what the UK standards are but here's the standard light fitting here:
There are four connections: Earth, Loop, Active and Neutral. I checked my work with a multimeter, but noticed that the neutral shorted to earth. There were two neutral wires joined together, but when seperated only one shorted to earth. I took this to be a fault, but found this to be the case on most of the other fittings -- and everything is working ok now that the power has been restored.
My question is why does the neutral short to earth? Only thing I can think of is that the power company
installed a special meter to monitor usage. I'm also curious as to whether the carboned fitting (once the water had gone) was responsible for continually tripping the circuit breaker until it was replaced.

 

[Darkwood]

Excluding your differing terms the system i assume may be the same as here in Sunny England in that the power is supplied via a star point transformer from the power company, in the design of these neutral and earth are created from a center tapping point of the transformer and are thus the same. You need to isolated the lighting at the fusing point by disconnecting L/N and earth then test it, if it still exists then there is a neutral earth fault on the lighting circuit.

 

[Brownout]

Thanks Darkwood for your quick reply,

As you've probably guessed I'm not a sparky and wouldn't usually go any further than replacing a fitting.
But it did strike me as odd having the neutral trip to earth. So I checked every light fitting on the circuit for faults, and even crawled around the ceiling looking for any nasty chewing by my namesake, -- all to no avail.
But I'll get it checked out at the switchboard end.

Thanks.

 

[Darkwood]

Thanks Darkwood for your quick reply,

As you've probably guessed I'm not a sparky and wouldn't usually go any further than replacing a fitting.
But it did strike me as odd having the neutral trip to earth. So I checked every light fitting on the circuit for faults, and even crawled around the ceiling looking for any nasty chewing by my namesake, -- all to no avail.
But I'll get it checked out at the switchboard end.

Thanks.

Dont quote me though as your countries power system may differ so you are probably best linking to a local forum to confirm what i suspect.